Flourescence of 3-(4'-AminophenyI)-7-aminocoumarins

Abstract

The fluorescence characteristics in DMF and fading behavior on polyamide film of 3-(4'- aminopheny1)-7-aminocoumarin and related compounds have been examined.
The intensity of fluorescence of trans-4, 4'-diaminostilbene C/D, 3-phenyl-7-aminocoumarin [3], 3-(4'-aminophenyl)-coumarin C5D, 3-(4'-aminophenyl)-7-aminocoumarin [7] and 3-(4'- aminopheny1)-4-methy1-7-aminocoumarin increased about 1.7, 0.86, 133, 1.9 and 1.6 times respectively, by acetylation. The photostability to fading decreases progressively in the following order: [7]>[5]>[9]>[3]>[1]. The photostability of the acetyl derivatives in [1] [7] and [9] was better than that of the amino derivatives, but the reverse was observed in [3] and [5]. The photofading rates of [5], [7] and [9] on the substrate decreased with their increasing concentration. In the cases of [3] and 3-(4'-acetylaminopheny1)-coumarin, however, the rate increased with increasing concentration. From these observations, together with previous results, a superimposed contribution of coumarin and trans-diaminostilbene was discussed for 3-(4'-aminophenyl)-7-aminocoumarin.